with congestion peaks. No CDN is 100% available. To get to
100%, one must federate (or combine) multiple CDNs.
The video player switches between the different bitrate
segments using the user’s bandwidth, buffer queues, and
other factors to determine the best bitrate given the situation.
In contrast, the outdated progressive download method
receives an entire file or stream at the same bitrate from
the same origin, regardless of changes in performance,
availability, and bandwidth.
The landscape is changing within the CDN market,
making multi-CDN and hybrid CDN solutions more prevalent.
Operators like Comcast, Telstra, and Verizon made major
investments to get into the CDN space. Regional CDNs have
materialized, focusing on specific markets or geographies.
Many content owners and aggregators are reevaluating their
single CDN strategies and considering active-active multi-CDN
strategies that push content directly to the “eyeball net works,”
with CDNs as a part of their offering. This strategy provides
superior performance for the viewer.
CDN MATURITY MODEL FOR VIDEO
Companies deploying online video begin a common
evolutionary process with either single-origin architecture
or a CDN for successful online video delivery. All CDNs
are subject to outages, however minor, that affect video
consumers. When viewers experience video buffering,
they quickly abandon video and web sessions—making
poor QoS the fastest way to lose video consumers. As needs
increase and cost of quality delivery mounts, organizations
will look for cost-effective delivery alternatives to a single
CDN. Companies learn they can use a multi-CDN approach
to control costs through better vendor management and
achieve 100% availability simultaneously.
Multi-CDN architecture could have prevented many well-
known outages of live events courtesy of active-active multi-
CDN architecture. CDNs have vastly different footprints, and
no CDN is the best in all locations. For this reason, it is common
to deploy a multi-CDN approach to support a broad geography.
As companies expand internationally, they realize
that a solution that worked well for the United States may
not be optimal for China, Brazil, or other global markets.
When organizations reach a certain size, they can further
improve performance and cut costs by deploying their own
infrastructure to support and augment video.
This CDN maturity model illustrates how companies
typically evolve. Not every company makes it all the way to a
“With adaptive bitrate streaming, every two or four
seconds, you have a chance to get content from a
different server, with seamless failover between
CDNs. You don’t get that benefit with progressive.”
—Will Law, Chief Architect, Media Division, Akamai